Your scenario (multi-vendor conference call, urgency of resolution) implies a problem in a production environment.
When architectures are fully end-to-end tested before being put into production, problems like these are eliminated long before solutions like complete hardware replacement are palatable to the business people signing the checks.
In my experience, these are best practices and extend to things like configuration management and code upgrades for everything from access switches to firewalls, load balancers, etc.

I'm happy to hear that you've found a strategy that works for you. There are many functional infrastructures out there that don't follow this model, and they are doing very well. The entire internet routing infrastructure is heterogeneous, for one example. I just think it's disingenuous to suggest that fundamental incompatibilities between major players with protocols like BGP and OSPF occur so often. Which equipment vendor do you work for?

Sorry, but no. I've been in the industry for over 10 years, and it's rare to experience these types of problems. Consumer-grade equipment is notorious for this type of thing, but it's much less common with a major vendor with a reputation to protect. Single vendor rarely means best of breed.